Regenerative system for braking.



'r mfg ng PATENTED DEC. l0, 1907.

W. I. SLICHTER.

RBGENERATIVE SYSTEM POR BRAKING.

lrwencgrt WQI'CGV Lllchter APPLICATION FILED JUNE 11, 1906.

wessleam Maud? @1% 'n 'W f mi? Acy.

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j I motives 1s the commutator series motor, preferably compensated.

to vsystems embodying this type of motor,

ciently asl braking may require; to enab e the motors to return f,energy Ibraking operatlon as braki use of' complicated paratus-'of anykin switch mechanism. In its broader aspects,

.howeyen'the invention is not confined to series'rirotor's operating onalternating currents butis `capable of wider -pointoft 'and'suppliedwith current through a transably4 but a single motor having its fie dwindjin'g connected to the transformer and operatto excite the fields ofthe remaining motors,..;and the other group having itsarmatures-connected to the transformer.

l' a proximate y 90 behind the line voltage.

STATES PATENTFFICE.

WALTER I. SLIOHTER, OF SCHENECTADY, NEW-YORK, COMPANY, A CORPORATION OFREGENEna'rrvE SYSTEM FonBRAmNG.

To all'whom 'it may Concern:

Be it known that I, WALTER I. SLICHTER, a citizen of theUnited' States,residing'at Schenectad countyof Schenectady, State of New York, haveinvented certain new and useful Improvements in Regenerative Systems forBraking, of whichthe following is a specification. v

In electric railways, 'particularly where long and severe grades are tobe encountered, it is highly advantageous to have the propelling motorsyact as -retarding a ents in4 descending the. grades. A type o motorwhich has given satisfaction in alternating currentsystems forpropelling cars ory loco-- r The present invention relates particularlyhaving for its objects to make it possible to operates'uch motorsconveniently and effienerators as occasion to the line'duringtheiroperationzas generators; and to adapt'them for 'ng generatorswithout the a paratus or auxiliary apother than a switch or application,as will be arent from the description and claims. ie f 0' the inventionfrom the stande series motor employed in groups Aormer: I divide themotors intotwo groups uringbraking, one group contai preferv*In thisarrangement the armature 'of the exciting motor generatescurrent whosevoltage is alproximately in phasewith the current in t e fpield Win ofthat motor and therefore e current in the field windings y which areconnected tothe armature of the exciti motor will-in turn beapproximately behind the voltage generated'in that armature and'.therefore'the voltage generated by the l Specification of l LettersPatent.

Application mum 11. 1906. Serial No. 321.105.

v It 1s of course not essential that which the car or trainmovesiduringthe brak'- ical construction armatures whichare'connected-'tolinel p-.

AssreNoR To GENERAL EL'EcTRIc NEW YORK. j,

Patented-Dec; ofi'eov.

proximately 90 behind the voltage gener- 55- ated by the first motor,-or180 behindjth f line voltage. The yrelation between th'eline voltage andthe voltage generated-'by the inotor armatures is therefore suchvthat'fcurrjentmay be returned to 'theline by the motors; 6'01541l i:oneof the' groups contain but one motorfbut-fitfis d' sirab e to have asmany motors inthefseon' group as possible inforderf'that thejbrakingaction may be most effective. `Thespefed a 6 ing ,action mayconveniently-be gontrolled'by` varying the pointofconnectongonlthetransl frmatures'orf former, either of 'thefgroup lthe-field winding ofthe exciter orfof bothrfzj h The resentmventior'rjinfits@v jvarious'fasi'h pects w1ll be moref lly urd'erstoodIand ther objects andia'dvant 'esthereofiwill ap` Pear fromthe'ffo'llowing taile'djscription I l' taken in connection ywith 75'drawing, wherein I f *ifi f1-f j Figure 1 indicatesdiagrar'nr'niticallyaifourgmotor equipment.. arranged :fin accordancewith the present inventiong'Fi .'-2findicates i the circu1tconnections'when't etmotlrsjare 80 operating as motors; and'Fig.3-"showlsythe 4 connections when the motors are serving as` I brakinggeneratorsQL y 'if' *fifi l Reference being hadfto thedrawings, M1`- M',Mand M* represent motors of the '85, compensated senesztype; Lindicates'elasu'p# ,ply conductor carrying ycurrent at'a pol tential;Tis a currentcollecting devicefcarried upon the car or"4 locomotiveandarranged to connect the supply conductor to fatrans- 90 former T1,which, asjillustrated,` may'ftake the form of a compensator; C amo'torcontroller of any usualtype arranged to connect w the motors tothe transformer and to-move the point of connection so as to vary thevolt e across the motors; R S is a reversing switc adapted to Vreversethe connections. between the series field windings and the armatures inorder toprovide for either' tion of rotation of the motors;l ands is acom` 100 mutating switch having and-brak?y ing positions. This switchapparatus lsall shownV in developed form since the mechan-V thereof Inaytake any usual or desired form. y

In order to start thecar in a'forward direction, the revers switch andthe commutating switch argloth moved to the posi-- l tions wherein theleft-hand row of movable contacts engage with the fixed contacts. Then,upon turning the controller into its first running position, currentflows from the tap a on the compensator, throu h contacts 2, 12, 13, and5, through resistance R, through the armatures and compensatin windingsof-motors M1, M2 andMa, throug contacts s, 3s, 5 and s of thecommutating switch, through the armature and compensating winding ofmotor M4, through contacts r, 2', r of the reversing switch, throughcontacts s, 2, s* of the commutating switch, through the series fieldwinding of motor M", through contacts s1, 1s and s of the commutatingswitch, through the series field windings of motors M1, M2 and M3,through contacts r, 1f, 1 of the reversing switch, through contacts s,4s, s of the commutating switch, to ound. When the controller has fullyreac ed its first running position, contact 1 on the controller engageswith contact 11, and the resistance R is cut out. The connections arenow as indicated inl full lines in Fig. 2. In the successive positionsof the controller, the point of connection between the motors and thecompensator is shifted from a, successively to and through taps b, c,and d, and finally to e, as indicated in dotted lines in Fig. 2.

For reverse o eration, the commutating switch is left in t e sameosition and the reversing switch is move into the osition wherein theright-hand set of mova le contacts engages with the fixed contacts.

When it is desired to cause the motors to operate as braking generatorsto retard the movement of the car or train, the reversing switch isplaced' or left in the position corresponding to the direction ofmovement of the car or train and the commutating switch is brought intothe position wherein the righthand row of movable contacts engages withthe fixed contacts. Then, upon operating the controller in the normalmanner, one terminal of the armatures of motors M1, M2 and M3 isconnected as before to tap a on the compensator but the other terminalis connected to ground through contacts s, 9 and S7 of the commutatingswitch; also current flows from tap a on the transformer, throughcontacts 9, 14, 15 and 10 of the controller, through contacts s", 8 ands* of the commutating switch, through the series field of motor M,through contacts s1, 6i4 and s, to ground. The armature and compensatingwinding of motor M4, it will be seen, are disconnected from theremaining armatures and a circuit may be traced from the right-handterminal of the armature of this motor, through contacts 1", 2r and r ofthe reversing switch (assuming the reversing switch to be in the forwardrunning position) through contacts s3, 7B, sz of the commutating switcthrough the series field windings of motors 1 A M1, Mz and M,through'ontacts r, 1f, r* of the reversing switch, through contacts ss,10i, s of thecommutating switch, to the left-hand terminal of thearmature of motor M. The circuit connections are now as in-- dicated infull lines in Fig. 3. By turning the controller through its successiverunning positions, the point ofconnection between the armatures ofmotors M1, Mz and M3 is shifted in succession to ta s b, c, d, and e,

each position of the contro ler providing for a different braking speedof the motors. Thus the speed of the car .or trainmay be controlled inthe same manner when descending inclines as during the ordinaryoperation thereof. Y

Although I have shown but one mode of controlling the braking speed ofthe motors, namely, by varyin the connection between the armatures of te motors M1, Mz and M3 85 and the compensator, it is of course evidentthat in its broader aspects the present invention contemplates means forvarying the circuit relations or conditions as to any of the severalelements which make up the comlete braking system. Furthermore, it maybe desirable at times to control the main circuits by motor controllersof the separatelyactuated contact type and to have the controller,reversing switch and commutating switch, or some of them, replaced bymaster controllers for governin the operation of thelseparately-actuated switch. The grouping of the motors may of coursealso be varied to suit individual requirements, it being, however,preferable to have as many armatures in the regenerative group aspossible in order to obtain the greatest braking effect and to return amaximum percentage of energy to the line.

What I claim as new, and desire'to secure by Letters Patent of theUnited States, is,-

1. The method of braking electrically in systems embodying 'a pluralitof motors adapted to drive a common loa which consists in operating aportion of the motors as separately-excited generators driven by theload and operating other of said motors as generators driven by the loadvand excited by current generated in the first-named portlon of themotors.

2. The method of braking electrically in systems embodying a pluralit ofmotors adapted to drive a common loa which consists in operating aortion of the motors as generators excited om the source of currentsupply, exciting other of the motors with thevcurrent so generated, andconnecting the armatures of the latter motors to the source of supply insuch relation. that the current generated in said armatures -may flow tosaid source of supply.

3. The method of braking electrically 1n systems comprising a pluralityof series motors connected to a common load, which con. 130

i enerators driven by the load and excited from the main source ofsupply and connectthe remaining motors to the source of supply andoperating them as generators 1 drlven by the load and excited by currentgenerated in the other motors.

4. The method of braking electrically in a system comprising a pluralityof motors connected to a common load and adapted to receive current froma transformer, which consists in operating a portion of said mo- .torsas generators driven by the load and excited from the transformer andoperating the other motors as generators driven by the load, excited bycurrent generated in the first-mentioned motors and returning current tothe transformers.

5. The method of braking electrically in a system comprising a pluralityof motors connected to a common load and adapted to receive current froma transformer, which consists in operating a portion of said motors asenerators driven by the load and excited I from the transformer andoperating the other motors as generators driven by the load, excited bycurrent generated in the first-mentioned motors and returning current tothe transformer, and varying the point of connection between one of theelements and the transformer. .nv 6. In combination, a plurality ofmotors connected to a common load, a source of current supply, andswitch mechanism constructed and arranged to connect said motors to saidsource of current supply to drive the load, or to connect a portion ofthe motors for operation as generators excited from said source ofsupply and driven by the load and s up lying current to the fieldwindings of the ot er motors.

7. In combination, a plurality of motors connected to a common load,means for supplying said motors with current in order to drive the load,and means for connecting one excited generator driven by the loa and forconnecting the other motors as generators driven by the load and excitedby current generated in the first motor.

8. In combination, a plurality of series motors connected to a commonload, a source of current su ply, and control apparatus constructed anarranged to connect said motors to said source of current su ply inorder to drive the load, or to connect t e field winding of one of themotors and the armatures of the other motors to the source of supply andconnect the remaining field windings to the armature terminals of thefirst motor.

9. In combination, a plurality of series motors connected to a commonload, a source of alternating current supply, and switch mechanismconstructed and arranged to of said motors for o eration as a se aratelysrstsfm-op'eratmgporton of themotors as l connect saidmotors tosaidsource of current 65 supply to drive the load, or to connect a portionof said motors for operation as generators driven by the load andexcited from said source of supply and connect the remaining motorsfor'operation as generators excited by current generated by the otherportion of motors and returning current to the source of supply.

1,0. In combination, a plurality of motors connected to a common load, asource of alternating current supply, and switch apparatus havingcontacts connected and varranged to connect said motors to said sourceof current su ply to drive the load, or to connect the fiel winding ofone motor and the armatures of the other motors in arallel circuitsto-the source of current supp y and connect the remaining field windingstothe terminals of the armature of the first motor.

11. In combination, a plurality of series motors connected to a commonload, a transformer, and switch apparatus having contacts connected andarranged to connect said motors to said transformer to drive the load,or to connect the field winding of one motor and the armatures of the4remaining motors in parallel circuits to said transformer, connect theremaining field windings acrossthe terminals of the armature of thefirst motor, and vary the point of connection of one of said parallelcircuits with the transformer.

12. In combination, a plurality of series f "i motors connected to acommon load, a transformer, and switch apparatus having contactsconnected and arranged t0 connect said motors to said transformer todrive the load, or to connect the field winding of one motor loof' andthe armatures of the remaining motors in parallel circuits to saidtransformer, connect the remaining field windings across the terminalsof the armature of the first motor, and vary the point of connection ofthe circuit containing the armatures with the transformer.

13. In combination, a plurality of series motors connected to a commonload, a transformer, control a paratus for connecting said motors to saitransformer and varying the point of connection with the transformer,and switch mechanism for modifying the circuit conditions vso that thenormal o eration of the control apparatus causes t e field winding ofone motor and the armatures of the other motors to be connected inparallel to the transformer and the remaining field windings to beconnected across the armature of the first motor.

14. In combination, a plurality of series motors connected to a commonload, a transformer, a controller constructed and arranged to connectsaid motors to said transformer to drive the load and to vary the pointof connection of the motors with the transformer, and a switch formodifying the the said motor armatures with the trans-` 10 circuitconditions in order that the normal former to be varied.

operation of the controller causesthe field In witness whereof, I havehereunto set Winding of one motor and the armatures kof my hand this5th' day of June, 1906.

the ot er motors to be connected to t e transformer in parallel circuitsand the re- WALTER I SLICHTER maining field Windin s to be connectedacross the terminals of the st motor, and the point of connection of thesaid circuit containing Witnesses:

BENJAMIN B. HULL, HELEN ORFORD.

